Field of the Invention
The present invention generally relates to energy storing suspension components for use in suspension systems for wheeled vehicles and trailers, and more particularly to energy storing suspension components having multiple tapers along their length, including support members, spring members, and the like, and to combinations of such energy storing suspension components with bushings. This disclosure presents several example embodiments that are representative of suspension components that may be utilized for particular purposes.
Discussion of the Prior Art
Wheeled vehicles and trailers commonly have suspension systems that utilize suspension components, such as support members, spring members, and the like, in suspending a vehicle or trailer frame and/or body assembly above and connecting to the axles to which wheels are rotatably connected. In this context, the frame and/or body assembly generally are referred to as the sprung portion of the vehicle or trailer and the wheels and respective axles, whether dealing with independent suspensions or solid axle suspensions, generally are referred to as the unsprung portions of the vehicle or trailer. For ease of reference, the suspension systems may be said to be a part of a chassis of a wheeled vehicle or trailer, with an understanding that the chassis may include a frame assembly or may be integrally constructed with a body assembly, such as in a so-called unibody construction.
Suspension systems typically include active components designed to isolate from the sprung portion the disturbances encountered by the unsprung portions, such as occur during acceleration and deceleration, or during jounce and rebound of the axle when traversing bumps in a road surface and the like, and to withstand lateral and roll forces, such as are encountered when cornering. Such suspension systems also typically are designed with an intended relative positioning of the unsprung portions to the sprung portion at rest and during normal operation of the vehicle or trailer. This relative positioning of the sprung portion to the unsprung portions can be influenced by component configurations and the way in which particular components are operatively coupled together, and generally results in what is commonly referred to as the ride height of a vehicle or trailer, which is associated with the height of a vehicle or trailer when the suspension system is at rest and in a normal condition ready to isolate disturbances.
Over time, a variety of different components and entire suspension systems have been developed to alter the capacity, ride height, ride comfort and handling characteristics of vehicles and trailers. The desire to alter these features with respect to suspensions may be prompted by a variety factors. However, suspension components, such as support members, spring members, and the like, play a dynamic role within a suspension system and their spring rates, both vertically and laterally, as well as stress levels and the ability to transfer loads to adjacent structures, present complex challenges.
For instance, a vehicle may utilize a traditional leaf spring member that is relatively thicker in an axle seat portion where the axle is coupled to the spring member. The spring member then may include a taper that decreases the thickness of the spring member at an end, to permit the end to be formed into an upturned eye. Such a spring member typically will have an axle seat portion that has a greater width than thickness and will be configured to have an adequate vertical spring rate to handle vertical loads and disturbances encountered on roads. Thus, this type of suspension component typically has a largest cross-sectional area in an axle seat portion, often with the axle seat portion having a greater width than thickness, and may taper to decrease in thickness and taper to increase in width at the spring member ends. In this manner, the spring member may maintain a somewhat similar or continuously decreasing cross-sectional area along its length.
However, such common prior art designs can lead to production of heavy spring members having an adequate vertical spring rate but a significantly higher lateral spring rate than otherwise would be necessary. This can result in unacceptable stress concentrations in the spring member near the axle seat portion under lateral bending, and in the transfer of excessive and potentially damaging loads to the coupling assemblies that are used to operatively couple the spring member to the chassis and to the axle. However, if a spring member and its coupling assemblies are configured with a combined bushing and lateral spring rate that is too low, then the lateral loads induced during articulation of the spring member will not be adequately transferred to the coupling components. In such instances, the loads are transferred to the vertical direction, resulting in higher and potentially unacceptable vertical stresses.
The present disclosure addresses shortcomings found in prior art suspension components for wheeled vehicles and trailers and in energy storing suspension components and bushings utilized therein.